1. Field of the Invention
The present invention relates to a high frequency speaker device.
2. Description of the Prior Art
Known is a speaker called a tweeter constructed in such a manner that a diaphragm such as of a cone type is attached to a piezoelectric element to be driven. In this type of speaker, an alternating voltage is applied to vibrate the piezoelectric element to drive the diaphragm so that a high frequency sound is reproduced. This type of speaker is described in Brazilian Patent No. 38401504 (Patent Application Number PI8401504), Japanese Patent Application Publication No. S46-2716, Japanese Patent Application Publication No. S47-2754, Japanese Patent Application Publication No. S53-38924, and Japanese Patent Application Laid Open No. H5-56497, and the like.
In these speakers, since components such as a piezoelectric element, a diaphragm, and the like are constructed independently and assembled, manufacturing process is complex. For that reason, relative positioning of each component is difficult, and a satisfactory sensitivity may not be obtained.
An object of the present invention, which was made in view of the above-mentioned aspects, is to provide a speaker device in which assembly is easy and satisfactory performance can be achieved.
A first aspect of the present invention is characterized in that a speaker device comprises a frame member, a piezoelectric element to which a sound signal is applied, a diaphragm attached to the piezoelectric element, a coil for boosting the sound signal, and a damper attached to the piezoelectric element in the opposite side face to the diaphragm to elastically support the piezoelectric element, wherein the coil is wound with respect to the frame member, and the damper is attached on the frame member.
With the speaker device constructed as described above, the coil is wound with respect to the frame member. The damper, the piezoelectric element, and the diaphragm are attached to the frame member. Thus, since the respective components are integrally constructed with the frame member, the manufacture of the speaker device becomes easy.
A second aspect of the present invention, in the speaker device according to the first aspect, is characterized in that the frame member comprises a cylindrical upper portion, a cylindrical lower portion having a smaller diameter than that of the upper portion, and a coupling portion for coupling the upper portion and the lower portion, and the coil is wound around the outer periphery of the lower portion. Thus, the lower portion of the frame member functions as a coil bobbin. Since the lower portion of the frame member has a smaller diameter than the upper portion""s diameter, the coil can be accommodated in the step between the upper portion and the lower portion of the frame member.
A third aspect of the present invention, in the speaker device according to the second aspect, is characterized in that the frame member comprises a bottom plate formed perpendicularly to the inner wall of the lower portion, and the damper is arranged on the bottom plate. Thus, the damper is stably fixed on the frame member. Further, since portions for receiving the respective components are formed in advance in the frame member, the respective components can be surely held in suitable places, and operations of the speaker device become stable. Specifically, since the diaphragm can be securely fixed between the frame member and the horn, characteristics of the speaker device can be stabilized. Thus, a speaker device with high sensitivity and low distortion can be achieved.
A fourth aspect of the present invention, in the speaker device according to the first aspect, is characterized by further comprising a horn arranged on a front face of the diaphragm. Thus, an appropriate directivity can be given to an acoustic signal outputted from the speaker device.
A fifth aspect of the present invention, in the speaker device according to the fourth aspect, is characterized in that an outer peripheral portion of the diaphragm is fixed to the horn. A sixth aspect of the present invention, in the speaker device according to the fifth aspect of the present invention, is characterized in that the outer peripheral portion of the diaphragm is held between an upper end portion of the frame member and the horn. Thus, the diaphragm and the horn are stably fixed mutually to each other.
A seventh aspect of the present invention, in the speaker device according to the first aspect, is characterized by further comprising an case body for accommodating the piezoelectric element, the diaphragm, the damper, the coil and the frame member, wherein the frame member is fixed to the case body. Thus, by accommodating the frame member holding the respective components integrally inside the case body, the speaker device can be easily assembled.
An eighth aspect of the present invention, in the speaker device according to the fourth aspect, is characterized by further comprising an case body for accommodating the piezoelectric element, the diaphragm, the damper, the coil and the frame member, wherein the frame member, the horn, and the case body are mutually fixed to each other. Thus, the respective components integrally attached to the frame member, the horn, and the case body are stably fixed mutually to each other.
A ninth aspect of the present invention, in the speaker device according to the third aspect, is characterized in that the frame member has a recess in a lower face of the bottom plate, and a circuit element is accommodated in the recess. Thus, even the circuit element can be fixed integrally to the frame member. Since the circuit element is stably held, the characteristics of the speaker device can be stabilized.
A tenth aspect of the present invention is characterized in that a speaker device comprises a frame member, a piezoelectric element to which a sound signal is applied, a diaphragm attached to the piezoelectric element, a horn arranged on a front face of the diaphragm, and a damper attached on the frame member and attached to the piezoelectric element in the opposite side face to the diaphragm to elastically support the piezoelectric element, wherein an outer peripheral portion of the diaphragm is held between an upper end portion of the frame member and the horn.
With this speaker device constructed as described above, the damper, the piezoelectric element and the diaphragm are attached on the frame member. The outer peripheral portion of the diaphragm is sandwiched between the upper end portion of the frame member and the horn. Thus, since the respective components are integrally constructed with the frame member, the manufacture of the speaker device becomes easy.
An eleventh aspect of the present invention, in the speaker device according to any one of the fourth, fifth, sixth, eighth and tenth aspects, is characterized in that the horn is composed of two members. Thus, formation of the horn itself as well as attachment of the horn to the speaker device can be made easy.
A twelfth aspect of the present invention, in the speaker device according to the eleventh aspect, is characterized in that the two members of the horn have different colors. Thus, the two members can be easily discriminated at the time of assembling the horn, and positioning or the like in assembly becomes easy. Since the horn is formed with the combination of different colors, visual effect as a speaker device is enhanced.